The potential of lipid dispersion as carriers of drugs to specific target cells has been recently demonstrated. This proposal concerns some of the basic chemical features involved in this phenomenon. One of our primary focuses will be on the long- and short-range forces which govern the selectivity of lipid vesicle-cell surface interactions. The adhesion process will be studied by analyzing the kinetics of excitation energy transfer between fluorophores bound to interaction membrane surfaces. The other major goal of this project is to illustrate the utility of the bilayer as a protective device for a bound reactive agent. The imidazole catalyzed hydrolysis of amphipathic aryl esters bound to the bilayer is the vehicle for this study of the effect of membrane composition on reactivity. It is hoped that this may suggest the design of more reactive alkylating agents for cancer chemotherapy, where degradation is retarded by viture of the hydrophobic lipid enclousure. Spinoffs from both of these projects include new methodologies for lipid synthesis and the study of membrane penetration and transmembrane flipping.